Horizontal Hall Sensor Isolation Structure for Higher Sensitivity
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Solution Overview
Problem
Traditional Hall devices suffer from issues such as short-circuiting, sensitivity restraint by electrode size, surface noise, and crosstalk, which compromise their performance and increase chip cost.
Innovation Solution
A horizontal Hall device utilizing deep trench isolation (DTI) and shallow trench isolation (STI) structures to control current paths, reduce surface noise, and prevent sensitivity restraint by electrode size, while achieving full isolation from other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional Hall device structure is used, then manufacturing is simple, but current short-circuiting occurs along device edges reducing sensitivity
Solution Approach 1:
The device is segmented into distinct functional regions using deep trench isolation structures that divide the current path into controlled segments. The isolation trenches separate the active Hall sensing region from edge regions, preventing current short-circuiting while maintaining manufacturing feasibility through standardized trench formation processes.
Solution Approach 2:
Different regions of the device are given different properties: the central active region maintains high conductivity for sensitivity, while edge regions are modified with isolation structures to prevent short-circuiting. This local differentiation allows the device to achieve both high sensitivity and reduced edge effects without requiring complete structural redesign.
2Manufacturing precision
If small electrode size is used, then sensitivity is improved, but initial offset increases and process challenges arise
Solution Approach 1:
Isolation structures serve as intermediary elements between the electrodes and the substrate edges. These structures mediate the current flow, allowing larger electrode sizes to be used without the traditional penalty of increased offset. The isolation structures act as buffers that prevent edge effects from affecting the electrode performance.
3Reliability
If junction isolation technique is used, then crosstalk between devices is reduced, but nonlinear resistance increases and chip area enlarges
Solution Approach 1:
The isolation approach transitions from two-dimensional junction isolation at the surface to three-dimensional deep trench isolation extending into the substrate. This vertical dimension provides effective crosstalk isolation between devices while maintaining a compact footprint, as the isolation occurs primarily in the depth direction rather than requiring additional lateral space.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances sensitivity by preventing short-circuiting, allows larger electrode sizes without sensitivity loss, and reduces initial offset and crosstalk, improving overall device performance and stability.
Implementation Method 1
current barrier layers are arranged between the induction electrodes of the second conduction type and the adjacent bias electrodes of the second conduction type, and the current barrier layers from the STI layer pass through the well layer of the second conduction type and the epitaxial layer of the first conduction type to be in contact with the BOX layer
Implementation Method 2
The Hall device converts magnetic field signals into electric signals, and the signal conversion efficiency and signal quality determine the overall performance of the Hall sensor
Data Source
AI summary
A horizontal Hall device includes a substrate layer and a BOX layer arranged on the substrate layer, where an epitaxial layer is arranged on the BOX layer, a well layer is arranged on the epitaxial layer, an STI layer is arranged on the well layer, a pair of induction electrodes and a pair of bias electrodes are arranged on the STI layer, ground electrodes are arranged on the epitaxial layer, and current barrier layers are arranged between the induction electrodes and the adjacent bias electrodes.